The competition is in its fourth year and growing, with a record 800 entrants submitting their cosmic photography. Winners were announced on Sept. 19 in four main categories — Deep Space, Our Solar System, Earth and Space, and Young Astronomy Photographer of the Year — and three special awards were also handed out.

The overall number one prize and top spot for the Deep Space category went to Martin Pugh for his amazing shot (above) of the Whirlpool Galaxy, which shows two galaxies colliding. Pugh also won in 2009 for his picture of the Horsehead nebula.

Other incredible images showed auroras, the Milky Way, and, particularly popular this year, the Transit of Venus. Being the last transit for 105 years, the event was highly photographed and the subject for two winners: Chris Warren, who won the Our Solar System category, and Paul Haese, who was ranked "highly commended" in the same group.

Here we take a look at all the winners, runners up, and highly commended images. If you’d like to see the photos in person, they will be exhibited for free from now until Feb. 2013 at the Royal Observatory.

The following captions are courtesy of the Royal Observatory Greenwich.

Above:

Whirlpool Galaxy

This beautifully composed image of the Whirlpool Galaxy combines fine detail in the spiral arms with the faint tails of light that show its small companion galaxy being gradually torn apart by the gravity of its giant neighbour. A closer look shows even more distant galaxies visible in the background.

Image: Martin Pugh, winner for Deep Space and overall winner

Simeis 147 Supernova Remnant

The photographer here set out to show not only the main subject of the image – a vast supernova remnant – but also the objects in the wide starscape that surrounds it. Straddling the constellations of Auriga and Taurus, Simeis 147 consists of the expanding debris of a massive star, which exploded around 40,000 years ago. As the wreckage continues to spread out into space it collides violently with the dust and gas between the stars, sculpting it into the glowing shells and filaments which have earned Simeis 147 the nickname of the "Spaghetti Nebula."

Image: Rogelio Bernal Andreo, runner-up for Deep Space

The Witch’s Broom

Highly Commended images for Deep Space category:

Part of the Veil Nebula, the "Witch’s Broom" (above) is the glowing debris from a supernova explosion – the violent death of a massive star. Although the supernova occurred several thousand years ago, the gaseous debris is still expanding outwards, producing this vast cloud-like structure. In this image narrowband filters have been used to greatly increase detail while giving a reasonable representation of the nebula’s colour.

Situated almost 250 million light-years away from us, the Perseus Cluster (above), also known as Abell 426, contains more than 500 catalogued galaxies. Some are spirals like the Milky Way while others are giant, smooth elliptical systems. Together they form one of the largest structures in the universe. Each smudge of light in this photograph contains millions, if not billions, of stars.

The spooky shapes (above) that seem to haunt this starry expanse are in fact cosmic dust clouds that fill huge volumes of space between the stars. The dust consists of tiny grains of minerals and ices and is an important building block for the formation of future stars and planets. The photographer had to travel 1,000 kilometres into the mountains of the Crimea to find a sky dark enough to capture this image.

Star Icefall

Taken in Nagano, Japan, this image shows Orion, Taurus and the Pleiades as the backdrop to an eerie frozen landscape. Though the stars appear to gleam with a cold, frosty light, bright blue stars like the Pleiades can be as hot as 30,000 degrees Celsius.

Image: Masahiro Miyasaka, winner Earth and Space

Green World

The aurora borealis traces the shifting patterns of the Earth’s magnetic field, creating a spectacular midwinter show in Nordland Fylke, Norway. The green light in this image comes from oxygen atoms high in the atmosphere, which have been energised by subatomic particles from the Solar Wind.

Image: Arild Heitmann, runner-up for Earth and Space

Summer Nights in Michigan

Highly Commended images for Earth and Space category:

This long-exposure image (above) contrasts the regular arcs of star trails with the chaotic swarming of fireflies – celestial, natural and man-made light are captured in a single photograph.

The Milky Way (above) arches over a mirror-like lake on the island of Reunion. At the bottom of the picture Piton des Neiges, the highest peak of Reunion Island, can be seen. The bright patch to the left of the image marks the bulge of stars at the heart of our Galaxy. The photographer waited two years before all the combined conditions were favourable to succeed with this photo.

Dark mountain peaks (above) frame two distinct lightscapes – the distant glow of towns and villages, and the majestic star fields of The Milky Way. Making the most of an August night, the photographer got this shot after trekking out to Uludag National Park near his hometown of Bursa, Turkey.

Transit of Venus 2012

Perhaps the biggest astronomical event of 2012 was the transit of Venus, which took place in June. Transits occur when Venus passes directly between the Earth and the Sun, appearing as a small black disc passing across the face of our parent star. The next transit will not take place for 105 years, in December 2117. This is a single unprocessed raw frame shot using a hydrogen-alpha (Ha) filter. It was captured early on the morning of 6 June between second and third contact, the photographer’s first and only glimpse taken through a thin patch in the clouds at Blackheath in London. The image captures the excitement of the 2012 transit of Venus, and the delight of observers in the UK who managed to catch a fleeting view despite the British weather.

Image: Chris Warren, winner Our Solar System

Mars in 2012

This sequence of photographs, taken in March 2012, uses the rotation of Mars to build up a complete view of the planet’s surface. It shows the gleaming north polar cap of frozen water and carbon dioxide, the red equatorial deserts and the darker southern highlands. The photographer has captured an amazing level of detail, including wispy clouds in the thin Martian atmosphere.

Image: Damian Peach, runner-up for Our Solar System

Comet C2009 P1 Garradd

Highly Commended images for Our Solar System Category:

Comet Garradd (above) was discovered in 2009 as it approached the inner Solar System. It became visible through binoculars in 2011 but has never been visible to the naked eye. To bring out the greenish glow of the comet’s halo the photographer has used a long exposure. The star trails show how he has tracked the comet’s orbital motion to keep it in the centre of the frame and the picture illustrates how the comet moved relative to the stars in 38 minutes.

Perhaps the biggest astronomical event of 2012 was the transit of Venus, which took place in June. Transits occur when Venus passes directly between the Earth and the Sun, appearing as a small black disc passing across the face of our parent star. They occur in pairs, eight years apart, with each pair separated by over a century. The previous transit was in 2004 and the next will not be until December 2117. This is a spectacular view of the active Sun (above), streaked and blotched with filaments, sunspots and prominences. Venus, a world almost exactly the same size as the Earth, seems dwarfed by the scale and power of our local star.

This portrait gallery (above) features four of our planetary neighbours in exquisite detail: the slender crescent Venus on 28 May; Mars on 29 February showing the famous Syrtis Major feature at the centre, and brilliant clouds over the Elysium Mons volcano on the right; Jupiter on 1 February showing Ganymede in transit, with Europa on the right, and its shadow cast onto the planet; Saturn close to opposition from 21 April showing the remains of the giant storm from the year before, as well as fine details within the ring system. The photographer shows the relative sizes of the planets as they appear to an observer on Earth. In reality Jupiter and Saturn would dwarf the other planets, but they are both much farther away from us.

Pleiades Cluster

Among the nearest star clusters to Earth, the stars of the Pleiades (Messier 45) are easily seen with the naked eye in the northern hemisphere’s winter skies. While it is often called the Seven Sisters, this beautiful photograph reveals many more of the hot, young stars which comprise the cluster. The young photographer has also captured the swirling wisps of a diaphanous gas cloud through which the cluster is currently passing, lighting it with reflected starlight. It was taken near dusk, with two frames and an hour of exposure.

Daytime Lunar Mosaic

This young photographer has knitted together several high-resolution images of the Moon in the daytime sky to form a colourful mosaic. This wonderfully detailed view shows the smooth dark maria (lunar "seas") and lighter, bumpier highlands of the Moon, both dotted with craters. The peaceful blue colour of the daytime sky is caused by scattering of blue light in the Earth’s atmosphere.

Heavenly Showers

Highly Commended in the Young Astronomy Photographer category:

This photograph (above) from the Young category of the competition skilfully frames the streaming, swirling patters of the Northern Lights with treetops below and a starry sky above. In the centre of the image, which was taken in the far North, close to the Arctic Circle, Orion the hunter is just visible through the bright auroral display. Taurus the bull and the bright Pleiades star cluster are seen in the clear area to the upper right.

This skilled young astrophotographer has captured a beautifully sharp and artfully framed detail of the Moon (above). The terminator – which separates the daytime and nighttime parts of the Moon – is aligned with the bottom edge of the photograph. The Sun’s light shines at a low angle onto the surface of the Moon just above this line, showing the contrast between smooth maria (lunar "seas") and rugged crater rims to the best advantage.

Earth and space are evenly weighted in this wonderfully framed image (above) of a Californian landscape beneath the Milky Way. The young photographer has chosen a view of an ancient Bristlecone Pine, which is over 4,000 years old, and whose sloping trunk and gnarled branches provide perfect counterpoint to the edge-on view of the starry disc and knotted structure of our galaxy.

Facing Venus-Jupiter Close Conjunction

This picture (above) was taken on the wet sand at low tide on the beach at Tréguennec in North West France and shows the conjunction of Venus and Jupiter. One of the astronomical highlights of 2012, the conjunction was the period when the two bright planets appeared conspicuously close together in the sky. Their apparent closeness was an optical illusion – Jupiter was in fact millions of kilometres further away than Venus. The photographer is pictured in the lower right corner of the frame and the Pleiades and Taurus are also visible on the upper left.

The photographer came across two hikers lost in the wilderness of Yosemite late one evening in July 2011. He captured this image (above) of the tiny figures in a small bubble of torchlight set within a vast, pitch-black forest beneath the immense dome of the sky. It highlights the wonder, beauty and awe of astronomy.

Images: 1) Facing Venus-Jupiter Close Conjunction, Laurent Laveder, winner People and Space. 2) Lost in Yosemite, Steven Christenson, runner-up People and Space.

Elephant’s Trunk With Ananas

The Elephant’s Trunk seems to uncoil from the dusty nebula on the right of the image, its tip curled around a cavity carved out by the radiation produced by young stars. Capturing a deep-sky object like this takes skill and painstaking attention to detail and is a great achievement for a newcomer to astrophotography.

Image: Lóránd Fényes, winner Best Newcomer

The Sunflower Galaxy

A spiral system like the Milky Way, Messier 63 has arms which encircle the yellowish centre of the galaxy like the petals of a flower, earning it the nickname of the Sunflower Galaxy. This image was captured by the young photographer using the Bradford Robotic Telescope in Tenerife, which he controlled over the internet.